If you want to make reservations through Interrail/Eurail that is done on the website, not in the app. Not all reservations can be made on the website and there is an extra charge of 2 EUR per reservation.
There are several options to make reservation and for some countries you have to make the reservations when you are in the country.
Here is good information on how to make reservations.
hello ! thank you for your reply, but will I get interrail reductions at the train station ?
And would you recommend to book the part I can online and later when i will be in the country the 2nd train?
Thank you !
Bonjour de Provence maintenant, beaucoup de soleil ici, but the rest is /en/
The PRIX for any REServ is the same for anyone-no discount, no surcharge. Except that via IR-site an extra 2€ is charged for their ´help´ in transmitting it to what you could have done right away.
BUT in some countries where a lot of those-mostly Hi-speed, like your TGV-trains are all-in: that means normal people buy a ticket with always REServ included- there are special supplmts for Passholders-on this national society of yours its 10€ IN a quota and 20 over that limit, Trips over borders=INTERnat. will cost often much, much more. It is quite often possible to avoid or reduce that by using local/regional=TER trains. But as you did not tell what trips/what day we cannot help you further in this
And once again-we have told this a few times every day; ESpagna is by far the worst for this, as nearly all trains MUST be REServed-can only be done at estacion/counter and the trains that nearly all newbees in training want to ride are often full days ahead in main summer. Your FR/SNCF comes neatly as 2nd-more for those of us who travel there but do not live.
hello ! thank you for your reply, but will I get interrail reductions at the train station ?
And would you recommend to book the part I can online and later when i will be in the country the 2nd train?
Thank you !
The Interrail pass is your ticket so there is really no Interrail discount, apart from on some special trains and some ferries.
How to make your reservation really depends where you will be travelling. In some countries like Switzerland there is mostly no need to make a reservation.
If you have questions on specific reservations you can ask here and here and hopefully you will get advice.
hello ! thank you for your reply, but will I get interrail reductions at the train station ?
And would you recommend to book the part I can online and later when i will be in the country the 2nd train?
In addition to the article posted by seewulf, there's an overview page with all countries and with the main reservation websites.
If you would like specific advice, then please post for the train(s) you would like to book: origin, destination, date, departure time.